Technical Field
The inventive concepts described herein relate to a semiconductor memory, and more particularly, relate to an operation method of a memory system that contains a nonvolatile memory and a memory controller.
Discussion of Related Art
A semiconductor memory device is a memory device which is fabricated using semiconductors such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), and so on. Semiconductor memory devices are divided into volatile memory devices and nonvolatile memory devices.
The volatile memory devices may lose stored contents at power-off. The volatile memory devices include a static RAM (SRAM), a dynamic RAM (DRAM), a synchronous DRAM (SDRAM), and the like. The nonvolatile memory devices may retain stored contents even at power-off. The nonvolatile memory devices include a read only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory device, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), a ferroelectric RAM (FRAM), and so on.
Some nonvolatile memories have an erase-before-write characteristic, which means that before data can be written into a location with previously written data, the previously written data needs to be erased. For example, a flash memory may have the erase-before-write characteristic. However, the operation performance of the memory device may decrease when the erasing performed before an overwrite takes a long time.